/**********************************************************************
 * Copyright (c) 2014 Pieter Wuille                                   *
 * Distributed under the MIT software license, see the accompanying   *
 * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
 **********************************************************************/

#include "hash.h"

// -----------------------
// sha256 operation
// -----------------------
// Operation macro definition
#define Ch(x,y,z)  ((z) ^ ((x) & ((y) ^ (z))))
#define Maj(x,y,z) (((x) & (y)) | ((z) & ((x) | (y))))
#define Sigma0(x)  (((x) >> 2 | (x) << 30) ^ ((x) >> 13 | (x) << 19) ^ ((x) >> 22 | (x) << 10))
#define Sigma1(x)  (((x) >> 6 | (x) << 26) ^ ((x) >> 11 | (x) << 21) ^ ((x) >> 25 | (x) << 7))
#define sigma0(x)  (((x) >> 7 | (x) << 25) ^ ((x) >> 18 | (x) << 14) ^ ((x) >> 3))
#define sigma1(x)  (((x) >> 17 | (x) << 15) ^ ((x) >> 19 | (x) << 13) ^ ((x) >> 10))
#define Round(a,b,c,d,e,f,g,h,k,w) do { \
    OhUint32Type t1 = (h) + Sigma1(e) + Ch((e), (f), (g)) + (k) + (w); \
    OhUint32Type t2 = Sigma0(a) + Maj((a), (b), (c)); \
    (d) += t1; \
    (h) = t1 + t2; \
} while(0)

#ifdef WORDS_BIGENDIAN
#define BE32(x) (x)
#else
#define BE32(p) ((((p) & 0xFF) << 24) | (((p) & 0xFF00) << 8) | (((p) & 0xFF0000) >> 8) | (((p) & 0xFF000000) >> 24))
#endif

// Initial hash value
OhVoidType sha256_init(ql_sha256_t* hash) {
    hash->s[0]  = 0x6a09e667ul;
    hash->s[1]  = 0xbb67ae85ul;
    hash->s[2]  = 0x3c6ef372ul;
    hash->s[3]  = 0xa54ff53aul;
    hash->s[4]  = 0x510e527ful;
    hash->s[5]  = 0x9b05688cul;
    hash->s[6]  = 0x1f83d9abul;
    hash->s[7]  = 0x5be0cd19ul;
    hash->bytes = 0;
}

// Perform one SHA-256 transformation, processing 16 big endian 32-bit words
OhVoidType sha256_transform(OhUint32Type* s, const OhUint32Type* chunk) {
    OhUint32Type a = s[0], b = s[1], c = s[2], d = s[3], e = s[4], f = s[5], g = s[6], h = s[7];
    OhUint32Type w0, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10, w11, w12, w13, w14, w15;

    Round(a, b, c, d, e, f, g, h, 0x428a2f98, w0 = BE32(chunk[0]));
    Round(h, a, b, c, d, e, f, g, 0x71374491, w1 = BE32(chunk[1]));
    Round(g, h, a, b, c, d, e, f, 0xb5c0fbcf, w2 = BE32(chunk[2]));
    Round(f, g, h, a, b, c, d, e, 0xe9b5dba5, w3 = BE32(chunk[3]));
    Round(e, f, g, h, a, b, c, d, 0x3956c25b, w4 = BE32(chunk[4]));
    Round(d, e, f, g, h, a, b, c, 0x59f111f1, w5 = BE32(chunk[5]));
    Round(c, d, e, f, g, h, a, b, 0x923f82a4, w6 = BE32(chunk[6]));
    Round(b, c, d, e, f, g, h, a, 0xab1c5ed5, w7 = BE32(chunk[7]));
    Round(a, b, c, d, e, f, g, h, 0xd807aa98, w8 = BE32(chunk[8]));
    Round(h, a, b, c, d, e, f, g, 0x12835b01, w9 = BE32(chunk[9]));
    Round(g, h, a, b, c, d, e, f, 0x243185be, w10 = BE32(chunk[10]));
    Round(f, g, h, a, b, c, d, e, 0x550c7dc3, w11 = BE32(chunk[11]));
    Round(e, f, g, h, a, b, c, d, 0x72be5d74, w12 = BE32(chunk[12]));
    Round(d, e, f, g, h, a, b, c, 0x80deb1fe, w13 = BE32(chunk[13]));
    Round(c, d, e, f, g, h, a, b, 0x9bdc06a7, w14 = BE32(chunk[14]));
    Round(b, c, d, e, f, g, h, a, 0xc19bf174, w15 = BE32(chunk[15]));

    Round(a, b, c, d, e, f, g, h, 0xe49b69c1, w0 += sigma1(w14) + w9 + sigma0(w1));
    Round(h, a, b, c, d, e, f, g, 0xefbe4786, w1 += sigma1(w15) + w10 + sigma0(w2));
    Round(g, h, a, b, c, d, e, f, 0x0fc19dc6, w2 += sigma1(w0) + w11 + sigma0(w3));
    Round(f, g, h, a, b, c, d, e, 0x240ca1cc, w3 += sigma1(w1) + w12 + sigma0(w4));
    Round(e, f, g, h, a, b, c, d, 0x2de92c6f, w4 += sigma1(w2) + w13 + sigma0(w5));
    Round(d, e, f, g, h, a, b, c, 0x4a7484aa, w5 += sigma1(w3) + w14 + sigma0(w6));
    Round(c, d, e, f, g, h, a, b, 0x5cb0a9dc, w6 += sigma1(w4) + w15 + sigma0(w7));
    Round(b, c, d, e, f, g, h, a, 0x76f988da, w7 += sigma1(w5) + w0 + sigma0(w8));
    Round(a, b, c, d, e, f, g, h, 0x983e5152, w8 += sigma1(w6) + w1 + sigma0(w9));
    Round(h, a, b, c, d, e, f, g, 0xa831c66d, w9 += sigma1(w7) + w2 + sigma0(w10));
    Round(g, h, a, b, c, d, e, f, 0xb00327c8, w10 += sigma1(w8) + w3 + sigma0(w11));
    Round(f, g, h, a, b, c, d, e, 0xbf597fc7, w11 += sigma1(w9) + w4 + sigma0(w12));
    Round(e, f, g, h, a, b, c, d, 0xc6e00bf3, w12 += sigma1(w10) + w5 + sigma0(w13));
    Round(d, e, f, g, h, a, b, c, 0xd5a79147, w13 += sigma1(w11) + w6 + sigma0(w14));
    Round(c, d, e, f, g, h, a, b, 0x06ca6351, w14 += sigma1(w12) + w7 + sigma0(w15));
    Round(b, c, d, e, f, g, h, a, 0x14292967, w15 += sigma1(w13) + w8 + sigma0(w0));

    Round(a, b, c, d, e, f, g, h, 0x27b70a85, w0 += sigma1(w14) + w9 + sigma0(w1));
    Round(h, a, b, c, d, e, f, g, 0x2e1b2138, w1 += sigma1(w15) + w10 + sigma0(w2));
    Round(g, h, a, b, c, d, e, f, 0x4d2c6dfc, w2 += sigma1(w0) + w11 + sigma0(w3));
    Round(f, g, h, a, b, c, d, e, 0x53380d13, w3 += sigma1(w1) + w12 + sigma0(w4));
    Round(e, f, g, h, a, b, c, d, 0x650a7354, w4 += sigma1(w2) + w13 + sigma0(w5));
    Round(d, e, f, g, h, a, b, c, 0x766a0abb, w5 += sigma1(w3) + w14 + sigma0(w6));
    Round(c, d, e, f, g, h, a, b, 0x81c2c92e, w6 += sigma1(w4) + w15 + sigma0(w7));
    Round(b, c, d, e, f, g, h, a, 0x92722c85, w7 += sigma1(w5) + w0 + sigma0(w8));
    Round(a, b, c, d, e, f, g, h, 0xa2bfe8a1, w8 += sigma1(w6) + w1 + sigma0(w9));
    Round(h, a, b, c, d, e, f, g, 0xa81a664b, w9 += sigma1(w7) + w2 + sigma0(w10));
    Round(g, h, a, b, c, d, e, f, 0xc24b8b70, w10 += sigma1(w8) + w3 + sigma0(w11));
    Round(f, g, h, a, b, c, d, e, 0xc76c51a3, w11 += sigma1(w9) + w4 + sigma0(w12));
    Round(e, f, g, h, a, b, c, d, 0xd192e819, w12 += sigma1(w10) + w5 + sigma0(w13));
    Round(d, e, f, g, h, a, b, c, 0xd6990624, w13 += sigma1(w11) + w6 + sigma0(w14));
    Round(c, d, e, f, g, h, a, b, 0xf40e3585, w14 += sigma1(w12) + w7 + sigma0(w15));
    Round(b, c, d, e, f, g, h, a, 0x106aa070, w15 += sigma1(w13) + w8 + sigma0(w0));

    Round(a, b, c, d, e, f, g, h, 0x19a4c116, w0 += sigma1(w14) + w9 + sigma0(w1));
    Round(h, a, b, c, d, e, f, g, 0x1e376c08, w1 += sigma1(w15) + w10 + sigma0(w2));
    Round(g, h, a, b, c, d, e, f, 0x2748774c, w2 += sigma1(w0) + w11 + sigma0(w3));
    Round(f, g, h, a, b, c, d, e, 0x34b0bcb5, w3 += sigma1(w1) + w12 + sigma0(w4));
    Round(e, f, g, h, a, b, c, d, 0x391c0cb3, w4 += sigma1(w2) + w13 + sigma0(w5));
    Round(d, e, f, g, h, a, b, c, 0x4ed8aa4a, w5 += sigma1(w3) + w14 + sigma0(w6));
    Round(c, d, e, f, g, h, a, b, 0x5b9cca4f, w6 += sigma1(w4) + w15 + sigma0(w7));
    Round(b, c, d, e, f, g, h, a, 0x682e6ff3, w7 += sigma1(w5) + w0 + sigma0(w8));
    Round(a, b, c, d, e, f, g, h, 0x748f82ee, w8 += sigma1(w6) + w1 + sigma0(w9));
    Round(h, a, b, c, d, e, f, g, 0x78a5636f, w9 += sigma1(w7) + w2 + sigma0(w10));
    Round(g, h, a, b, c, d, e, f, 0x84c87814, w10 += sigma1(w8) + w3 + sigma0(w11));
    Round(f, g, h, a, b, c, d, e, 0x8cc70208, w11 += sigma1(w9) + w4 + sigma0(w12));
    Round(e, f, g, h, a, b, c, d, 0x90befffa, w12 += sigma1(w10) + w5 + sigma0(w13));
    Round(d, e, f, g, h, a, b, c, 0xa4506ceb, w13 += sigma1(w11) + w6 + sigma0(w14));
    Round(c, d, e, f, g, h, a, b, 0xbef9a3f7, w14 + sigma1(w12) + w7 + sigma0(w15));
    Round(b, c, d, e, f, g, h, a, 0xc67178f2, w15 + sigma1(w13) + w8 + sigma0(w0));

    s[0] += a;
    s[1] += b;
    s[2] += c;
    s[3] += d;
    s[4] += e;
    s[5] += f;
    s[6] += g;
    s[7] += h;
}

// Perform sha-256 on data
OhVoidType sha256_write(ql_sha256_t* hash, const OhByteType* data, OhSizeType len) {
    OhSizeType bufsize = hash->bytes & 0x3F;
    hash->bytes += len;
    while (bufsize + len >= 64) {
        // Fill the buffer, and process it.
        memcpy(((unsigned char*)hash->buf) + bufsize, data, 64 - bufsize);
        data += 64 - bufsize;
        len  -= 64 - bufsize;
        sha256_transform(hash->s, hash->buf);
        bufsize = 0;
    }
    if (len) {
        // Fill the buffer with what remains.
        memcpy(((unsigned char*)hash->buf) + bufsize, data, len);
    }
}

// Perform last sha-256 and output hash result
OhVoidType sha256_final(ql_sha256_t* hash, OhByteType* out32) {
    static const OhUint8Type pad[64] = {0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
    OhUint32Type sizedesc[2];
    OhUint32Type out[8];
    int i = 0;
    sizedesc[0] = BE32(hash->bytes >> 29);
    sizedesc[1] = BE32(hash->bytes << 3);
    sha256_write(hash, pad, 1 + ((119 - (hash->bytes % 64)) % 64));
    sha256_write(hash, (const OhByteType*)sizedesc, 8);
    for (i = 0; i < 8; i++) {
        out[i] = BE32(hash->s[i]);
        hash->s[i] = 0;
    }
    memcpy(out32, (const unsigned char*)out, 32);
}


// -----------------------
// hmac operation
// -----------------------
// Initial hmac parameter
OhVoidType hmac_init(ql_hmac_t* hash, const OhByteType* key, OhSizeType keylen) {
    int n;
    OhByteType rkey[64];
    if (keylen <= 64) {
        memcpy(rkey, key, keylen);
        memset(rkey + keylen, 0, 64 - keylen);
    } else {
        ql_sha256_t sha256;
        sha256_init(&sha256);
        sha256_write(&sha256, key, keylen);
        sha256_final(&sha256, rkey);
        memset(rkey + 32, 0, 32);
    }
    // compute outer
    sha256_init(&hash->outer);
    for (n = 0; n < 64; n++) {
        rkey[n] ^= 0x5c;
    }
    sha256_write(&hash->outer, rkey, 64);
    // compute inner
    sha256_init(&hash->inner);
    for (n = 0; n < 64; n++) {
        rkey[n] ^= 0x5c ^ 0x36;
    }
    sha256_write(&hash->inner, rkey, 64);
    memset(rkey, 0, 64);
}

// Perform hmac on data
OhVoidType hmac_write(ql_hmac_t* hash, const OhByteType* data, OhSizeType size) {
    sha256_write(&hash->inner, data, size);
}

// Perform last hmac and output result
OhVoidType hmac_final(ql_hmac_t* hash, OhByteType* out32) {
    OhByteType temp[32];
    sha256_final(&hash->inner, temp);
    sha256_write(&hash->outer, temp, 32);
    memset(temp, 0, 32);
    sha256_final(&hash->outer, out32);
}

// -----------------------
// rfc6979 operation
// -----------------------
// Initial rfc6979 parameter
OhVoidType rfc6979_init(ql_rfc6979_t* rng, const OhByteType* key, OhSizeType keylen) {
    ql_hmac_t hmac;
    static const OhByteType zero[1] = {0x00};
    static const OhByteType one[1] = {0x01};

    memset(rng->v, 0x01, 32); /* RFC6979 3.2.b. */
    memset(rng->k, 0x00, 32); /* RFC6979 3.2.c. */

    /* RFC6979 3.2.d. */
    hmac_init(&hmac, rng->k, 32);
    hmac_write(&hmac, rng->v, 32);
    hmac_write(&hmac, zero, 1);
    hmac_write(&hmac, key, keylen);
    hmac_final(&hmac, rng->k);
    hmac_init(&hmac, rng->k, 32);
    hmac_write(&hmac, rng->v, 32);
    hmac_final(&hmac, rng->v);

    /* RFC6979 3.2.f. */
    hmac_init(&hmac, rng->k, 32);
    hmac_write(&hmac, rng->v, 32);
    hmac_write(&hmac, one, 1);
    hmac_write(&hmac, key, keylen);
    hmac_final(&hmac, rng->k);
    hmac_init(&hmac, rng->k, 32);
    hmac_write(&hmac, rng->v, 32);
    hmac_final(&hmac, rng->v);
    rng->retry = 0;
}

// generate rfc6979 result
OhVoidType rfc6979_gen(ql_rfc6979_t* rng, OhByteType* out, OhSizeType outlen) {
    /* RFC6979 3.2.h. */
    static const OhByteType zero[1] = {0x00};
    if (rng->retry) {
        ql_hmac_t hmac;
        hmac_init(&hmac, rng->k, 32);
        hmac_write(&hmac, rng->v, 32);
        hmac_write(&hmac, zero, 1);
        hmac_final(&hmac, rng->k);
        hmac_init(&hmac, rng->k, 32);
        hmac_write(&hmac, rng->v, 32);
        hmac_final(&hmac, rng->v);
    }

    while (outlen > 0) {
        ql_hmac_t hmac;
        int now = outlen;
        hmac_init(&hmac, rng->k, 32);
        hmac_write(&hmac, rng->v, 32);
        hmac_final(&hmac, rng->v);
        if (now > 32) {
            now = 32;
        }
        memcpy(out, rng->v, now);
        out += now;
        outlen -= now;
    }

    rng->retry = 1;
}

// clear global parameter
OhVoidType rfc6979_final(ql_rfc6979_t* rng) {
    memset(rng->k, 0, 32);
    memset(rng->v, 0, 32);
    rng->retry = 0;
}

// We feed a byte array to the PRNG as input, consisting of:
// - the private key (32 bytes) and message (32 bytes), see RFC 6979 3.2d.
// - optionally 32 extra bytes of data, see RFC 6979 3.6 Additional Data.
// - optionally 16 extra bytes with the algorithm name (the extra data bytes
//   are set to zeroes when not present, while the algorithm name is).
OhVoidType rfc6979_nonce(OhByteType* nonce32, const OhByteType* msg32, const OhByteType* key32, const OhByteType* algo16, OhVoidType *data, OhSizeType counter) {
    OhByteType keydata[112];
    ql_rfc6979_t rng;

    int keylen = 64;
    int i;
    memcpy(keydata, key32, 32);
    memcpy(keydata + 32, msg32, 32);
    if (data != NULL) {
        memcpy(keydata + 64, data, 32);
        keylen = 96;
    }
    if (algo16 != NULL) {
        memset(keydata + keylen, 0, 96 - keylen);
        memcpy(keydata + 96, algo16, 16);
        keylen = 112;
    }

    rfc6979_init(&rng, keydata, keylen);
    memset(keydata, 0, sizeof(keydata));
    for (i = 0; i <= counter; i++) {
        rfc6979_gen(&rng, nonce32, 32);
    }
    rfc6979_final(&rng);
}
